Managing application performance is crucial for successful virtualization projects. Modern virtualization aware and cloud aware APM tools are a critical part of successfully ensuring the performance and availability of business critical applications and performance critical applications in shared and dynamic data centers created by either virtualization or the use of a cloud:
The most frequently encountered barrier to virtualizing business critical applications is a “concern” on the part of the application owners that the applications will “not run as well”, or “not perform as well” in a shared and dynamic virtual environment as it does in a dedicated physical environment. Depending upon who has what political power, these concerns can stop the project to virtualize these applications dead in its tracks.
You can read more here: Virtualizing Business Critical Applications – Managing Applications Performance